Lightning-arrester.



F. S. CHAPMAN.

LIGHTNING ARRBSTER.

APPLICATION FILED FEB. 2, 1910 1,017,649 Patented Feb. 20, 191.2.

k F l E i g/J j 5 Z j UNITED STATES P A rEivT OFFICE.

FRANK S. CHAPMAN, OF TOLEDO, OHIO, ASSIGNOB TO THE NATIONAL ELECTRIC SPECIALTY COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO.

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Specification of Letters Patent.

Patented Feb. 20, 1912.

or detrimental; devices of this general class.

being ordinarily termed lightning arresters, although obviously they may be employed for shunting ofi' high potential charges from a circuit, whether due to lightning or to other causes, either external to the'circuit or within the same.

Lightning arresters have been constructed in a number of different Ways. Most commonly, they involve a. grounded line in which are electrodes spaced apart so as to form a gap, this gap being through the air. Because of the high resistance of air the gap between the electrodes is necessarily narrow. A narrow gap, however, is very soon clogged because of the disintegrating action of the electric current on the electrodes, which are commonly carbon. As a result the ordinary lightning arresters of carbons, held apart by a mica spacer, will seldom satisfactoril stand more than one static discharge 0 high voltage. After such a discharge, or in any event after several such discharges, the gap between the electrodes is part1 or wholly bridged over, with the result t at a part or all of the service current escapes to the ground neces sit-sting the removel, and scraping of the electrodes or the substitution of new electrodes. In order to obviate these disadvantages in the ordinary constructions of lightning arresters, I have devised a lightning arrester, the salient characteristic of which is that the discharge takes place in a vacuum instead of in the air, this arrangement permitting the electrodes to be spaced farther apart so that the danger of bridging over the gap is very materially diminished. Several difi'erent forms of appartus involving this general principle have been shown and described in my co-pending applications Nos. 541,548 and 541,550, filed February 2, 1910, respectively.

The object of my present invention is to provide a vacuum lightning arresterusing the term in its widest significance-which shall have certain new and improved features relating particularly to convenience in handling and using the device, inserting it in and removing it from the circuit and to facilitate manufacture, which will be hereinafter fully described.

The invention has for a further object to provide a device of the character to be hereinafter described which can be used for other purposes than as a lightning arrcster or device for shunting high potential charges from an electric circuit. Certain of these other uses will be described herein, it being my object to cover the new combinations of my present invention, regardless of the use to which they may be put.

The invention in certain preferred embodiments is illustrated in the accompanying drawings, wherein Figure 1 is a sectional view through a switch-board taken on line 1lof Fig. 2. Fig. 2 a sectional view on line.22 of Fig. 1. Fig. 3 a diagram illustrating one useful application of the device of my invention. Fig. 4 a sectional view similar to thatof Fig. 1, illustrating the use of thedevice in connection with a metallic circuit. Fig. 5 is a diagram illustrating the circuits in such an installation, and Figs. 6, 7 and 8 are diagrams illustrating different uses to which my invention can be put.

Like characters of reference indicate like parts in the several figures of the drawings.

Referri'n first to Figs 1 and 2, A represents the insulating base of a. switch-board, or other supporting device, B, B a air of spring clips which are secured to the use A by the screws 0 and nuts 0; the screws C being also provided with the nuts D, by which they may beused as binding posts for the conductors -E and E. Between the clips or terminals B is laced a preferably glass vessel F from t e interior of which the air has been partially exhausted. Within the vessel F are the electrodes G, G, preferably made of carbon. Preferably, the electrodes are spaced apart by turning in the ends of the vessel at the points indicated by the letters f. Preferably, the vessel f is formed with recesses and with the flat sides 7, f and secured to the outside of the vessel at these places are the contact plates H, II, the latter being electrically connected through the sides of the vessel with the electrodes respectively adjacent thereto by means of the short conductors /1..

which can be turned to the dotted line position to include in the circuit one of the devices b, above described. If the latter is properly designed with reference to the in- In Fig. 3 l have shownlhe device above tensity of the va ulun and the size and spacdescribed employed as a lightning arrester ing of the electrodes (1 when the discharge in connection with a. grounded circuit or is passed through it by turning the switch service line. The latter is indiea ted by the S to its dotted line position, the presence of letter I and is supplied by a battery or other the glow will indicate that the discharge is source of current J and contains an instrusutlieieut to produce a proper spark, the abinent K, such as a telephone or other device l sence ot the glow indicating the reverse. which it is desirable to protect from the dc- Obviously the arrangement may be such structive effects of a high voltage discharge that each of the spark plug circuits may be The lightnin f arrestel, the vacuuirrchamber i so tested. The use oi the device in this conof which is indicated by I is interposed in J neetion, as a detector is not specifically a grounded line I), E. If the line I be r elain'led herein, the combination being made comes charged with electricity at an abnorthe subject matter of a co-pending applimally high potential, whether because of cation filed by me February 2, 1910, Serial lightning or any other cause, the high volt- No. 541,550. age will be shunted off through the arrester In Fig. 7 the device of my invention is F, the electrodes of which (i are spaced employed for preventing or reducing a apart at a sutlicient distance and the vacuum surge from the opening of a switch inthe in which is of suflieient intensity to prevent circuit. The circuit T contains the battery the normal service charge from going to the J and the switch U, a conductor 25 conground over the line E, E, while permitting nects the switch terminals U and contains the static to so discharge. an arrester F of the character described, the In Fig. 4 I have shown two vacuum vacuum chamber of which is indicated at F. chambers, of the character described, ar- When. the switch is opened, the potential, ranged so as to connect with a circuit at two resulting from the surge, is shunted around different points, for example, with the two through the arrester, the latter permitting aerials of ametallic circuit. the discharge of the abnormal potential Fig. 5 is a diagram of the circuits. In while not allowing the flow through the conthese figures the spring terminals B, B are ductor t of a: normal charge. The value of spaced wide enough apart for two vacuum the device is inc-teased in the case shown in chambers F, F, between which extends a Fig. 8 in which the circuit: T is the pri- 10 contact plate L, connected with the binding mary circuit of an induction coil for transpost M. The non-grounded circuit N is forming the current into one of higher volt:- connected at two points on opposite sides age, a secondary being shown at: V. In of the device 0 to be protected with the such case the openin of the switch U rebinding )osts O, C, respectively, by the eon sults in the further increase of the voltage ductors 1 P. Q is a grounded line leading at the air gap, due to the inductive influfrom the binding post M of contact L. Obence of the charge. in the circuit V on the viously, this protects the instrument: or other circuit T. device 0 from abnormal chargescn either The employment of the arrester in Figs. aerial of the circuit N. I 7 and 8 prevents destructive arcing at the In Fig. 6 I have shown an application of switches. the device of my invention. When a dis- It will be seen that my invention contemchargc passes between the electrodes G, G, plates an arrangement ,of parts permitting contained within the vacuum chamber II, the vacuum chamber and electrodes to be a violet glow is clearly discernible. In Fig. readily removed from the circuit and re- 6 I have illustrated how this circumstance placed. lVhen one of the vacuum chambers enables the device to be used to determine mcomes worn out: or broken it can be simwhether a conductor is charged, and by a ply slipped out: from between the terminals proper design of the device, whether the and a new one putin its place. charge is sufficiently strong. For example, The terms vacuum and vacuum it is desirable that the sparking apparatus chamber have been used in their strictly of an automobile gasolene engine should be, accurate sense as implying the nearest posprovided with some means for determining t sihle approximatimi to the complete removal whether the spark plugs of the various of air and gases but in the whole general cylinders are operating properly. sense as iiulieating a considerable reduced In Fig. 6, R represents one of the spark pressure. plug circuits, the spark plug being indiit. is obvious that the intensity of the cated at r and the battery at J. vacuum, that is the degree to which the ex- S is a switch which, as shown in the Full haustion of the air may be carried in any lines, normally closes the circuit R but vase, will depend upon the normal voltage 136 of the line on which the device is to be used or upon other circumstances depend ent upon the particular use of the device in a given installation. The resistance al't'orded by the vacuum gap varies with the degree of vacuum, and with the residual gases in the vacuum chamber.

While the device as described is par ticularly intended to be used on relatively low tension lines, such for example as telephone lines, it is capable, by a designcf the parts which will be obvious, of being used in connection with circuits carrying higher voltages.

I claim:

1. In a device of the character described, the combination with holding means comprising two terminals, one of which at least is a spring, of a sealed evacuated glass ves sel provid exteriorly on opposite sides with cont' lates adapted to make contact with said terminals and interior-1y with electrodes electrically connected with said corntact plates respectively; the walls of said vessel hcing Formed so as to provide in ward pro i-clions which hold the electrodes in fixed position and spaced apart.

'2. In a device of the character described, the combination with holding means comn'ising two terminals one of which at least is a spring, of a scaled evacuated glass vessel tornicd cxtcriorly on opposite sides with recesses and provided. with contact plates in said recesses, said vessel being adapted to be held between said terminals with the contact plates in contact therewith, and a pair of electrodes arranged in said vessel and electrically connected with said contact plates; the walls of said vessel being formed with inward projections between said electrodes which hold the electrodes in fixed position and spaced apart.

FRANK S. CHAPMAN.

\Vitncsses R'H. TRUMAN,

E. L. BRainEnT.

It is hereby certified that in Letters Patent ,No. 1,017,649; granted February 20, 1912, upon the 'applimfiion of Frank Chapman, of Toledo, Ohio, for an improvement in [)ightning-Arrefithrgf an error appears in the printed specification rel' uiring rurrectiou as fulknwf: Pug g 2 line 121, after the word used insert the word 11m; and t hab thv said Lettvrs Pat-(fut should be read with this correction therein that the same may conform to the fihcurd of the case in the Patent Oflice.

Signdhnd sealed this 26th day of March, A. D., 1912.

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